The invention relates to a method for the wireless transmission, in closed spaces, of the energy emitted by at least one light source, in which the light energy emitted by the light source is received by at least one solar cell module arranged in the closed space and is converted into electricity. It also relates to a device for carrying out this method.
The term “wireless energy transmission” in this case is defined quite generally as the transmission of electrical energy from an energy source to an electrical load without an electrically conducting physical connection. The most common form in which such a wireless energy transmission is carried out is by means of induction, wherein this is typically realized by resonant magnetic induction. Other methods make use of the transmission of electromagnetic radiation in the form of microwaves or laser light. Recent developments on this topic can be found on the internet, for example under the link “http://zomobo.net/Power-beaming”.
A method of the above type, in which the light energy emitted in an enclosed space by a light source is received directly by a solar cell module and converted into electricity, has been disclosed in US Patent 2009/010 3 925 A1. In addition, DE 10 2009 055 684 A1 discloses a system for increasing the yield of photovoltaic systems for feeding energy into an AC voltage network, for supporting a heating system and providing hot water, in which the photovoltaic system is operated by the supply of artificial light. DE 102 33 005 B4 further discloses a similar arrangement, in which a device for supplying electricity to a sensor at a high electrical potential in a painting system comprises an artificial light source and PV modules. Finally, from DE 100 37 254 A1 an energy storage device is known which consists of an evacuated storage vessel that has a highly reflective coating over its entire internal surface and is connected via air-locks to one other vessel at each of its input and output ports. The input receptacle in this known arrangement is also reflectively coated, while the output vessel is completely lined with solar cells fitted with ports extending to the outside for supplying the electricity.
While the above methods and arrangements are all intended for terrestrial purposes and are designed accordingly, the article “Wireless Power Transmission for Solar Power Satellite (SPS)”, for example, by N Shinohara, in www.sspi.gatech.edu/wptshinohara.pdf, describes a method for the wireless transmission of the energy emitted by at least one light source, which, in particular, can be used in space missions. In these applications the weight of the cables and their requirements for the installation of sensors in the launcher rocket present a serious problem for efficient energy transmission. In addition, the use of batteries for a wireless sensor network introduces maintenance issues for these batteries. Finally, the so-called energy harvesting methods with a thermocouple element or a piezoelectric element also present problems, in particular with regard to the identification of suitable sites and the correct placement of the elements in closed spaces.